Cat - Nasopharyngeal Polyps

What are nasopharyngeal polyps?

Polyps are a form of growth. However they are benign and not growths of the cancerous type that tend to spread. The nasopharyngeal form of polyps arise in the middle ear, the compartment just behind the ear-drum. As they become larger they grow down the Eustachian tube which is the tube that connects the middle ear to back of the throat and expand, filling and blocking the cavity at the back of the mouth. The main effect of the polyp is to interfere with breathing. They obstruct the passage of air so affected cats usually develop a distinctive snorting sound as they breathe. Secondary bacterial infection can develop due to the blockage and accumulation of secretions and this may result in a discharge from the nose and sneezing.

The original reason for polyps to develop is not known. It is thought that they may result as a response to chronic inflammation. Sometimes they seem to develop after 'cat flu' or respiratory infection. Nasopharyngeal polyps tend to occur in younger cats and they are frequently under a year of age.

How are nasopharyngeal polyps diagnosed?

It may be possible to see the polyp at the back of the throat when examining the mouth. The polyp may be hidden behind the soft palate (roof of the mouth) but it may be obvious that there is something behind the soft palate, pushing it forward. Some cats with nasopharyngeal polyps become touchy about having their head handled and sedation or anaesthesia may be necessary to allow a satisfactory examination to be undertaken. Radiography (x-rays) can help to identify nasopharyngeal polyps and the use of a specialist endoscope (tiny video camera) may enable direct visualisation of the polyp. If your veterinary surgeon is uncertain whether a mass is a polyp, a biopsy for microscopic pathological examination may be recommended. In some cats with nasopharyngeal polyps, part of the polyp may penetrate the ear drum and grow out through the ear canal. This may be visible on close inspection of the ear.

How are nasopharyngeal polyps treated?

It is usually very straightforward to remove the bulk of a nasopharyngeal polyp by simply pulling it away from the back of the throat which will immediately alleviate the clinical signs. However this will usually leave the stalk remaining which has grown down the Eustachian tube from the middle ear, and polyps usually recur after removal by simple traction. It is possible to perform a bulla osteotomy which is an operation involving creating an opening into to the middle ear cavity. This allows removal of the source of the polyp. This is the most effective treatment for preventing recurrence but is a major surgical procedure and surgical complications are common. An alternative approach, but which is less effective at preventing recurrence is to use drugs such as corticosteroids to try to control the inflammation which is thought to stimulate the growth of the polyp.

What is the outlook for cats with nasopharyngeal polyps?

Although there is a risk of recurrence, nasopharyngeal polyps can be resolved effectively in most cats and long-term outlook is very good. Although side effects are quite common with surgery, most are transient and cats generally do well in the long-term.